Rosacea is a chronic inflammatory skin disorder whose pathogenesis is unclear. Here, several lines of evidence were provided to demonstrate that mTORC1 signaling is hyperactivated in the skin, especially in the epidermis, of both rosacea patients and a mouse model of rosacea‐like skin inflammation. Both mTORC1 deletion in epithelium and inhibition by its specific inhibitors can block the development of rosacea‐like skin inflammation in LL37‐induced rosacea‐like mouse model. Conversely, hyperactivation of mTORC1 signaling aggravated rosacea‐like features. Mechanistically, mTORC1 regulates cathelicidin through a positive feedback loop, in which cathelicidin LL37 activates mTORC1 signaling by binding to Toll‐like receptor 2 (TLR2) and thus in turn increases the expression of cathelicidin itself in keratinocytes. Moreover, excess cathelicidin LL37 induces both NF‐κB activation and disease‐characteristic cytokine and chemokine production possibly via mTORC1 signaling. Topical application of rapamycin improved clinical symptoms in rosacea patients, suggesting mTORC1 inhibition can serve as a novel therapeutic avenue for rosacea.

Rosacea is a common chronic skin disorder of unknown etiology. While population prevalence rates range 0.2-22% in Europe and North America, prevalence in China is currently undetermined. We conducted a large populationbased case-control study to determine the present epidemiological status of rosacea in China, involving 10 095 participants aged 0-100 years (mean age, 35.5 ± 19.1; 50.5% female). A census of rosacea among 15 communities in Changsha in south central China was conducted with skin examination by board-certified dermatologists. Rosacea was observed in 3.48% (95% confidence interval, 3.13-3.85%) of the study population. Subtype distribution was erythematotelangiectatic in 47.6%, papulopustular in 35.0% and phymatous in 17.4%. Family history was noted in 37.8% and ocular symptoms in 31.3%. Associations with rosacea were observed for melasma, hypertension, hyperthyroidism and breast cancer in females (P < 0.05), and also for hyperthyroidism and peptic ulcers in males (P < 0.05). Our results provide baseline information about epidemiological aspects of rosacea in China.

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BackgroundThere is currently no study that has evaluated the differences in epidemiological and clinical characteristics among rosacea patients according to different facial sites.MethodsClinical and demographic data were obtained from 586 rosacea patients. The patients were divided into four groups based on the main sites involved with the rosacea lesions (full-face, cheeks, nose, or perioral involvement). Clinical signs were measured through self-reported, dermatologist-evaluated grading of symptoms, and physiological indicators of epidermal barrier function.ResultsThere were 471 (80.4%), 49 (8.4%), 52 (8.9%), and 14 (2.4%) cases in the full-face, cheek, nasal and perioral groups, respectively. Compared with the healthy control, the full-face group had lower water content and higher transepidermal water loss (TEWL) in the cheeks, and chin; the perioral group had lower water content and higher TEWL in the chin; while the nasal group had the normal water content and TEWL. Compared with the full-face group, the nasal group had more severe phymatous changes, less severe self-reported and dermatologist-evaluated grading of symptoms. All the patients in the perioral or the nasal group had their first rosacea lesions start and remain at the chin or on the nose. In the full-face group, 55.8% of patients had their lesions start with the full face, 40.1% on the cheek, and the rest (4.1%) on the nose.ConclusionSignificant differences in clinical features were observed among rosacea patients with lesions at four different sites. The lesion localization of each group was relatively stable and barely transferred to other locations.

Although patients with rosacea often consult dermatologists for dietary factors that might be related to their skin disorders, few studies have been conducted to research the relationship between rosacea and dietary factors. The purpose of this study was to evaluate the potential relationship between rosacea and diet among the large Chinese population with rosacea, which would provide dietary guidelines for patients with rosacea. A multicenter case–control study was conducted. The feeding frequency 2 years before the occurrence of rosacea was collected by standardized questionnaires. Multiple logistic regression analysis was used to calculate risks related to the diet. One thousand three hundred and forty‐seven patients with rosacea and 1290 controls were enrolled in our study. We found that high‐frequency intake of fatty food and tea presented a positive correlation with rosacea, while high‐frequency dairy product intake showed significant negative correlation with rosacea. Sweet food, coffee and spicy food appeared to be independent of any subset of rosacea in our study. However, high‐frequency dairy product intake showed a borderline beneficial effect on rosacea severity. We further analyzed the correlation between diet and the subtype of rosacea. We found that high‐frequency fatty intake was associated with erythematotelangiectatic rosacea (ETR) and phymatous rosacea, while high‐frequency tea intake was only associated with ETR. In addition, high‐frequency dairy product intake showed negative correlations with ETR and papulopustular rosacea. Rosacea is associated with some dietary factors, and our study is valuable in establishing dietary guidelines to prevent and improve rosacea.